• 제목/요약/키워드: Oxidation stress

검색결과 391건 처리시간 0.029초

Dislocation-Free Shallow Trench Isolation 공정 연구 (A study on the Dislocation-Free Shallow Trench Isolation (STI) Process)

  • 유해영;김남훈;김상용;이우선;장의구
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
    • /
    • pp.84-85
    • /
    • 2005
  • Dislocations are often found at Shallow Trench Isolation (STI) process after repeated thermal cycles. The residual stress after STI process often leads defect like dislocation by post STI thermo-mechanical stress. Thermo-mechanical stress induced by STI process is difficult to remove perfectly by plastic deformation at previous thermal cycles. Embedded flash memory process is very weak in terms of post STI thermo-mechanical stress, because it requires more oxidation steps than other devices. Therefore, dislocation-free flash process should be optimized.

  • PDF

Physiological Roles of Erythroascorbate Peroxidase In Candida albicans

  • Kwak, Min-kyu;Kang, Sa-Ouk
    • 한국생물물리학회:학술대회논문집
    • /
    • 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
    • /
    • pp.41-41
    • /
    • 2001
  • Ascorbate peroxidase catalyze the oxidation of ascorbic acid through the reaction with hydrogen peroxide. Ascorbic acid are utilized as a substrate in oxidative stress. In Candida albieans, ascorbic acid is used as antioxidants, so called D-erythroascorbic acid (EASe). Oxidative stress change concentrations of EASC resulting in interaction with alternative oxidase (AOX).(omitted)

  • PDF

태계($KI_3$) 전침의 항산화 효과에 대한 실험적 연구 (The Study on the Effect of Electroacupuncture at Taegye($KI_3$) on Anti -oxidation)

  • 김성래;홍권의;김영일
    • Journal of Acupuncture Research
    • /
    • 제24권3호
    • /
    • pp.99-109
    • /
    • 2007
  • Objectives : The purpose of this study is to observe the anti-oxidative effects of electroacupuncture at Taegye($KI_3$) in rats. Methods : The methods are measures of experimental items including change of body weight, relative liver weight, level of alblumin, total bilirubin, LDL-cholesterol, LDH, GOT and GPT in blood serum, level of SOD, GSH, catalase, NO and MDA concentration in liver, histological change of liver. Results: 1. The $KI_3$-EA group lost weight in the beginning, and gained it gradually. 2. The liver ratio of the $KI_3$-EA group increased compared to the holder group, without any statistical significance. 3. The SOD activity, Glutathione concentration, and Catalase concentration increased, and the NO concentration and MDA concentration decreased in the $KI_3$-EA group significantly, compared to the holder group. 4. $KI_3$-EA group had more similar density to the normal group, than the holder group. Conclusion : The electroacupuncture application on Kb has anti-oxidation effect, by improving the body defence against the oxidation stress- induced cytotoxicity, and by supressing the oxidative liver damage.

  • PDF

Antioxidant enzymes as redox-based biomarkers: a brief review

  • Yang, Hee-Young;Lee, Tae-Hoon
    • BMB Reports
    • /
    • 제48권4호
    • /
    • pp.200-208
    • /
    • 2015
  • The field of redox proteomics focuses to a large extent on analyzing cysteine oxidation in proteins under different experimental conditions and states of diseases. The identification and localization of oxidized cysteines within the cellular milieu is critical for understanding the redox regulation of proteins under physiological and pathophysiological conditions, and it will in turn provide important information that are potentially useful for the development of novel strategies in the treatment and prevention of diseases associated with oxidative stress. Antioxidant enzymes that catalyze oxidation/reduction processes are able to serve as redox biomarkers in various human diseases, and they are key regulators controlling the redox state of functional proteins. Redox regulators with antioxidant properties related to active mediators, cellular organelles, and the surrounding environments are all connected within a network and are involved in diseases related to redox imbalance including cancer, ischemia/reperfusion injury, neurodegenerative diseases, as well as normal aging. In this review, we will briefly look at the selected aspects of oxidative thiol modification in antioxidant enzymes and thiol oxidation in proteins affected by redox control of antioxidant enzymes and their relation to disease. [BMB Reports 2015; 48(4): 200-208]

Antioxidative Properties of Sachil-Tang Extract

  • Yi, Hyo-Seung;Moon, Jin-Young
    • 동의생리병리학회지
    • /
    • 제23권4호
    • /
    • pp.872-882
    • /
    • 2009
  • Sachil-Tang (SCT) has been traditionally used as a prescription of spasm of the esophagus by stress, pectoralgia and oppressive feeling of the chest in Oriental medicine. This study was carried out to investigate the antioxidant activities of the ethanol extract of SCT and its inhibitory effect on intracellular oxidation and vascular cell adhesion molecule-1 expression in human umbilical vein endothelial cells (HUVECs) using various methods. The SCT extract showed a strong inhibitory effect on free radical generating model systems, including DPPH radical, superoxide anions, hydroxyl radical, peroxynirite and nitric oxide. Besides, the SCT extract exhibited a strong inhibitory effect on lipid peroxidation in rat liver homogenate induced by $FeCl_2$-ascorbic acid, and protected plasmid DNA against the strand breakage in a Fenton's reaction system. The SCT extract also inhibited copper-mediated oxidation of human low-density lipoprotein (LDL), and repressed relative electrophoretic mobility of LDL. Furthermore, the SCT extract protected intracellular oxidation induced by various free radical generators and inhibited expression of vascular cell adhesion molecule-1 (VCAM-1) in HUVECs. These results suggest that SCT can be an effective natural antioxidant and a possible medicine of atherosclerosis.

후확산 공정 변수가 p+ 실리콘 박막의 잔류 응력 분포에 미치는 영향 (Effects of Drive-in Process Parameters on the Residual Stress Profile of the p+ Silicon Film)

  • 정옥찬;양상식
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
    • /
    • pp.245-247
    • /
    • 2002
  • The paper represents the effects of the drive-in process parameters on the residual stress profile of the p+ silicon film. For the quantitative determination of the residual stress profiles, the test samples are doped via the fixed boron diffusion process and four types of the thermal oxidation processes and consecutively etched by the improved process. The residual stress measurement structures with the different thickness are simultaneously fabricated on the same silicon wafer. Since the residual stress profile is not uniform along the direction normal to the surface, the residual stress is assumed to be a polynomial function of the depth. All of the coefficients of the polynomial are determined from the deflections of cantilevers and the displacement of a rotating beam structure. As the drive-in temperature or the drive-in time increases, the boron concentration decreases and the magnitude of the average residual tensile stress decreases. Also, near the surface of the p+ film the residual tensile stress is transformed into the residual compressive stress and its magnitude increases.

  • PDF

Biochemical Characterization of the Dual Positional Specific Maize Lipoxygenase and the Dependence of Lagging and Initial Burst Phenomenon on pH, Substrate, and Detergent during Pre-steady State Kinetics

  • Cho, Kyoung-Won;Jang, Sung-Kuk;Huon, Thavrak;Park, Sang-Wook;Han, Ok-Soo
    • BMB Reports
    • /
    • 제40권1호
    • /
    • pp.100-106
    • /
    • 2007
  • The wound-inducible lipoxygenase obtained from maize is one of the nontraditional lipoxygenases that possess dual positional specificity. In this paper, we provide our results on the determination and comparison of the kinetic constants of the maize lipoxygenase, with or without detergents in the steady state, and characterization of the dependence of the kinetic lag phase or initial burst, on pH, substrate, and detergent in the pre-steady state of the lipoxygenase reaction. The oxidation of linoleic acid showed a typical lag phase in the pre-steady state of the lipoxygenase reaction at pH 7.5 in the presence of 0.25% Tween-20 detergent. The reciprocal correlation between the induction period and the enzyme level indicated that this lag phenomenon was attributable to the slow oxidative activation of Fe (II) to Fe (III) at the active site of the enzyme as observed in other lipoxygenase reactions. Contrary to the lagging phenomenon observed at pH 7.5 in the presence of Tween-20, a unique initial burst was observed at pH 6.2 in the absence of detergents. To our knowledge, the initial burst in the oxidation of linoleic acid at pH 6.2 is the first observation in the lipoxygenase reaction. Kinetic constants (Km and kcat values) were largely dependent on the presence of detergent. An inverse correlation of the initial burst period with enzyme levels and interpretations on kinetic constants suggested that the observed initial burst in the oxidation of linoleic acid could be due to the availability of free fatty acids as substrates for binding with the lipoxygenase enzyme.

탄소강의 열간연성 거동에 미치는 산화의 영향 (Effect of Oxidation on Hot Ductility Behavior of Plain Carbon Steel)

  • 박태은;이운해;손광석;이성근;김인수;임창희;김동규
    • 대한금속재료학회지
    • /
    • 제48권5호
    • /
    • pp.394-400
    • /
    • 2010
  • The effects of oxidation behavior on the hot ductility of plain carbon steels were investigated at various temperatures in order to simulate the continuous casting process more precisely, in which the process undergoes in air atmosphere rather than Ar atmosphere. The high temperature oxidation behavior and scale morphology of the carbon steels exposed to the air and Ar atmosphere at various temperatures were also investigated in order to assess the mechanism of the RA value decreasing in an air atmosphere. The RA values obtained from the air atmosphere were marked below 45% by the test temperature, except for over 1000${^{\circ}C}$, with the RA values remaining in low values in both the low and high temperature region, at which the RA values generally recovered in the Ar atmosphere. The surface roughness of the specimen was developed by external and internal oxidation when the specimen was deformed in an air atmosphere at high temperature, with the result being the stress concentrated at the roughness of the specimen surface, resulting in low RA values. The hot ductility in the air atmosphere was found to be likely controlled by the oxidation rate instead of the microstructures corresponding to test temperatures.

스트레스균형이 이루어진 $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$ 유전체 멤브레인의 제작 (Fabrication of Stress-balanced $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$ Dielectric Membrane)

  • 김명규;박동수;김창원;김진섭;이정희;이종현;손병기
    • 센서학회지
    • /
    • 제4권3호
    • /
    • pp.51-59
    • /
    • 1995
  • 실리콘기판 위에 스트레스균형이 이루어진 150 nm-$Si_{3}N_{4}$/300 nm-$SiO_{2}$/150 nm-$Si_{3}N_{4}$ 구조의 평탄한 유전체 멤브레인을 제작하였다. 이 멤브레인의 스트레스 특성평가를 위하여 stress-deflection, stress-temperature 및 스트레인 진단용 시험패턴의 특성을 측정분석하였고, 중간에 있는 $SiO_{2}$층을 PECVD, LPCVD 및 APCVD방법으로 각각 증착하여 $SiO_{2}$층의 증착방법에 따른 적층 유전체박막의 스트레스특성에 대해서도 논의하였다. 대부분의 경우 적층 유전체 멤브레인에 인장스트레스가 존재하였으나, $SiO_{2}$층의 증착방법과 거의 무관하게 $1,150^{\circ}C$의 후습식산화로 실리콘기판에 의해 멤브레인에 나타나는 인장스트레스의 균형을 얻을 수 있었다. 온도변화에 따른 멤브레인에서의 스트레스 변화특성으로 부터 후산화처리를 하지 않는 경우에는 중간의 $SiO_{2}$ 층으로 APCVD방법에 의해 증착된 LTO가 더 적합한 것으로 나타났다.

  • PDF

알루미늄을 투여한 흰쥐의 해마와 대뇌피질에서 Reactive Oxygen Species 생성으로 인한 생체거대분자의 산화적 손상 (The Effects of Oxidative Stress Induced by Aluminum on Cellular Macromolecules in the Hippocampus and Cerebral Cortex of Rats)

  • 문철진;고현철;신인철;이은희;문해란
    • Toxicological Research
    • /
    • 제20권3호
    • /
    • pp.213-223
    • /
    • 2004
  • This work aimed to study the effectiveness of cellular oxidative parameter (malondial-dehyde, protein carbonyl, and 8-hydroxy-2'deoxyguanosine). The experimental groups were aluminum treated rats and control rats. Aluminum treatd rats were given intraperitoneally aluminum nitrate nonahydrate ($Al^{3+}$, 0.2 mmol/kg) daily for 30 days except Sunday. Control rats were injected 1 ml of saline. After the dose, rats were decapitated and hippocampus and cerebral cortex were removed. The measured parameters were tissue malondialdehyde (MDA, index of lipid peroxidation), protein carbonyl (index of protein oxidation), 8-hydroxy-2'-deoxy-guanosine (8-OHdG, index of DNA oxidation), reduced glutathione (GSH) levels as well as glutathione reductase (GR) and catalase. AI concentrations in the tissues were also measured. All results were corrected by tissue protein levels. The results were as followed; 1. The concentrations of AI in the cortex and hippocampus were significantly higher in the AI-treated rats than in the control rats. 2. Antioxidative enzyme's activity, catalase and GR, were significantly higher in the AI-treated rats than the control rats. GSH levels were also higher in the AI-treated rats. 3. MDA, protein carbonyl, and 8-OHdG concentration of AI-treated rats were significantly higher than those of control rats. 4. The concentrations of antioxidants, and oxidative stress parameter were correlated with the concentrations of AI in hippocampus and cerebral cortex. Catalase and GR activity were also correlated with the concentration of AI. Based on these results, it can be suggested that intraperitoneally injected AI was accumulated in the brain and induced the increase of antioxidant levels and antioxidative enzyme activity. Also, the oxidative products of cellular macromolecules are significantly related to tissue AI concentration. Therefore MDA, protein carbonyl, and 8-OHdG are useful markers for oxidative stress on cellular macromolecules.